The present invention relates to dispersants based on polyamines or polyimines containing side chains based on two or more poly(oxy-C1-6-alkylenecarbonyl) compounds and methods for their preparation and their use.
Dispersants containing one or more poly(oxy-C1-6-alkylenecarbonyl) chains are known and are usually prepared by copolymerization with ε-caprolactone. They are generally used for dispersing of particulate solid particles in an organic solvent and contain either acidic and/or basic end groups.
Dispersants containing terminal-based groups are described in application WO 94/21368 and include reaction products of polyethyleneimine with ε-caprolactone in the presence of aliphatic and hydroxyaliphatic carboxylic acids which act as chain terminators during the polymerization of the ε-caprolactone. A disadvantage of the dispersants mentioned is their high tendency to crystallize, whether in the presence or absence of solvents, which makes practical use of such dispersants difficult. The crystallized dispersants have to be correspondingly heated and then homogenized prior to the use thereof.
WO 99/55763 and WO 01/21298 describe the production of dispersants based on the use of at least two lactones. The production of such dispersants enables the suppression of the crystallization. However, the lactones used therein are costly and not always freely available on the market.
The problem addressed by the present invention is therefore that of providing dispersants that are easy and inexpensive to prepare and have only a low tendency to crystallization, and at the same time do not have any detriments in the technical application tests, for instance the rub-out test, the color test or the viscosity test.